This invention relates to nuclear reactors, and in particular to liquid metal cooled nuclear reactors. Such reactors are generally of the fast breeder type.
A liquid metal cooled nuclear reactor is usually housed in a steel vessel which is itself enclosed within a concrete containment vault, and in order to prevent damage to the concrete due to heat radiated from the vessel containing the reactor core it is usual to interpose thermal insulation between vessel and vault.
It is an object of the present invention to provide a construction of thermal insulation capable of protecting the concrete of the vault from heat radiation from the reactor vessel, even under fault conditions.